1. Field of the Invention
The present invention relates to the field of power generation from a renewable power source. More particularly, the invention relates to the use of a rotor and vanes in a flowpath of a flow medium, for generating electrical power.
2. Description of the Prior Art
Humans have extracted power from the energy of flowing streams for centuries. Typically, this is done by forcing the water over a dam and using the head pressure from the drop to turn a turbine. Building a dam is a very costly effort and the barrier to flow caused by the dam typically has serious negative consequences for wildlife and, particularly, for migrating species of fish. As a result, people have tried many different ways of extracting energy from flowing water simply by relying on the kinetic energy of a flowing stream. Wind turbines rely on the flow of air and are becoming ever more popular as a source of clean energy. One type of wind turbine is the Savonius wind turbine, which is a drag-type vertical axis wind turbine generator that typically has a very low efficiency, around 15%. As a result, the Savonius wind turbine is generally not deemed suitable for electricity generation, except for small-scale production. This type of turbine is also used in installations that require slow rotation and high torque, such as in pumping water or grinding grain.
What is needed therefore is apparatus for and a method of extracting energy from a flow medium. What is further needed is such apparatus and method that is mechanically uncomplicated, yet efficient. What is yet further needed is such apparatus and method that is suitable for extracting energy from very low flow currents, with high efficiency and low impact on the natural environment and wildlife.